From the mechanistic standpoint, some of the issues could be addressed by animal models. Regarding the tumor promoter mechanism, a recent report (Wong et al., 2011a) showed that ethanol promotion of mammary tumors in transgenic mice depended upon ovarian hormones, clearly consistent with an estrogen mediated tumor promoter mechanism. However, the extent to which mammary tumors in this and other rodent models are related to breast cancer in humans is an important unanswered question.
